The present invention relates to rotary switches and particularly to rotary switches employed for program selection for the operating cycle of appliances such as washing machines and dishwashers. In appliances such as washing machines and dishwashers manufactured for the household market, the use of a rotary knob or dial for selecting the desired machine program or cycle has found widespread user acceptance and renders the appliance operation quite simple. Additionally, a push-to-start or push-to-turn function of the rotary control knob has also found widespread user acceptance in such household appliances. These features have their origin in appliances which utilized an electromechanical programmer timer, particularly a programmer timer employing a plurality of switches actuated by a rotary advanced program cam. Typically, such electromechanical programmer timers employed a rotary cam advanced through one full revolution for the complete machine cycle; and, the user rotates the cam to a desired position for selecting the desired portion of the complete machine cycle.
However, with the advent of relatively low cost microprocessors it has been desired to provide electronic control of appliances such as washing machines and dishwashers and to eliminate the time based electromechanical programmer timer. However, it has also been desired to retain the rotary knob type program selection and to also retain the push-to-start feature of the user control knob. Such an arrangement of a rotary user control providing inputs to an electronic controller without a plurality of cam actuated switches has proven to be difficult due to the problem of providing a discrete electrical signal for a particular position of the rotary control knob such that the controller can determine the particular selected rotary position of the knob. Where numerous discrete positions of the rotary user control knob are desired, it is prohibitive to provide an individual switch for each position and thus, it has long been desired to find a way or means of providing such a discrete electrical indication without requiring an individual switch for each position.